This invention relates to universal type exercising gyms, and more particularly to such exercise gyms utilizing fluid pressure cylinders which replace more conventional dead weights, coil springs, elastic bands and the like for resisting movement of the exercise lever arms associated therewith.
Universal gyms using hydraulic cylinders as source of resistance for exercising purposes are known in the art, and illustrative of the general principles are U.S. Pat. No. Des. 230,613 and U.S. Pat. Nos. 4,275,892 and 4,397,462.
All of the above illustrate basically an exercise lever assembly attached pivotally to a vertical upright which is either mounted to a base platform or bench, or to a wall, or both. An hydraulic or pneumatic cylinder also connects the lever assembly to the upright below the pivot axis of the lever and is adjustably mounted to the lever in order to vary the working stroke of the cylinder and lever arm and for adjusting the resistance applied to the lever by the cylinder.
In each of the utility patents listed above, the working range of the lever arm of the gym is adjustable by moving the connection of the cylinder inwardly and outwardly along the arm, the resulting positions of the arm and its throw thus being determined by the particular stroke of the piston and the particular disposition of the piston mount on the lever arm. The resistive force applied against the lever arm is varied in the first utility patent listed above by moving the connection point of the cylinder to the lever arm longitudinally along the lever arm toward and away from its pivotal mount to the wall bracket, thereby reducing the working stroke of the exercise lever arm as resistance on it by the cylinder is increased. In the second reference above, the resistance offered against the exercise arm by the pneumatic cylinder is varied through use of a complex construction involving a check valve connecting the cylinder to a large air reservoir and an outside air pump which together control the desired pressure.
In all universal gym constructions utilizing an exercise lever arm assembly, the applicant is not aware of any gym arranged to provide an arm working stroke that allows the handle members associated therewith to travel substantially vertically from their fully lowered to their fully raised positions during exercising. The inherently arcuate paths of travel of the handle members of universal gyms of the prior art consequently require the user to step backward as the lever arm is raised, to maintain balance; causes increased strain on the users back; and creates a potentially dangerous situation should the user be thrown off balance and lose his grip on the weighted arm.